In the past week, the city has had three major fires which have destroyed a total of nine buildings and left more than 180 people homeless.

Lewiston Police say they're still trying to figure out what caused another major fire this morning that destroyed two apartment buildings on Bartlett Street.

In the past week, the city has had three major fires, which destroyed a total of nine buildings and left more than 180 people homeless. Two 12-year-old boys are facing separate arson charges in connection the first two fires.

At a news conference this afternoon, city officials said they haven't yet determined what caused the third fire. But they said they're taking steps to prevent more, including boosting patrols in a 25 to 30 block area of the city, and increasing checks on vacant buildings.

Authorities are also urging residents to dispose of trash and debris around buildings, along with other waste that could be set on fire. A curfew for juveniles of 10 p.m. on weeknights and midnight on weekends remains in effect.

Gov. Paul LePage is scheduled to visit the city on Tuesday.This story was reported by Susan Sharon and written by Barbara Cariddi.